Published online by Cambridge University Press: 05 March 2021
Intraguild predation is the killing and consuming of a heterospecific competitor that uses similar resources as the prey, and also benefit from preying on each other. We investigated the foraging behaviour of the gallmidge, Aphidoletes aphidimyza, a predator of aphids used for biological control that is also the intraguild prey for most other aphid natural enemies. We focus on how aphid alarm pheromone can alter the behaviour of the gallmidge, and predation by the anthocorid bug Orius laevigatus (O. laevigatus). We hypothesised that gallmidges would respond to the presence of (E)-β-farnesene (EBF) by leaving the host plant. Since feeding by Aphidoletes gallmidge larvae does not induce EBF emission by aphids, this emission indicates the presence of an intraguild predator. We found that gallmidge larvae reduced their foraging activities and left the plant earlier when exposed to EBF, particularly when aphids were also present. Contrastingly, gallmidge females did not change the time visiting plants when exposed to EBF, but lay more eggs on plants that had a higher aphid density. Lastly, EBF reduced the number of attacks of the intraguild predator, O. laevigatus, on gallmidge larvae, potentially because more gallmidges stopped aphid feeding and moved off the plant at which point O. laevigatus predated on aphids. Our work highlights the importance of understanding how intraguild predation can influence the behaviour of potential biological control agents and the impact on pest control services when other natural enemies are also present.
Present address: Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran.
Present address: Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
Present address: Department of Entomology, Schal's Lab, North Carolina State University, Raleigh, North Carolina, USA.